The HIV/AIDS pandemic is the gravest infectious disease threat to human health and well-being in the 21st century. In the third decade of HIV/AIDS we still do not have a cure, a vaccine, or a microbicide. International collaborative HIV/AIDS research, and the training needed for developing country scientists to lead that research, remains an urgent global health priority. The Johns Hopkins University Fogarty AIDS International Training & Research Program (Hopkins AITRP) is now in its 20th year of providing such training. This application seeks to continue and expand the program for an additional 5 years of support. The Hopkins AITRP is centered in the Department of Epidemiology of the Johns Hopkins Bloomberg School of Public Health and includes faculty from the Schools of Medicine and Nursing. Primary partner countries include China, Ethiopia, India, Malawi, Thailand, and Uganda. Newer partner countries include Vietnam and South Africa. In Years 16-20, we trained 38 long-term degree candidates: 14 doctoral, 21 masters' and 3 bachelors'; 146 short term trainees; and conducted 76 In-Country Group Trainings for some 3,499 trainees in 11 countries. Of the 256 trainees who began and completed their training in Years 16-20, 254 have returned to home countries, a rate of return of 99.2%. We have emphasized training in HIV epidemiology, clinical trials, HIV vaccinology, Good Clinical and Laboratory Practices, pediatric HIV/AIDS; research ethics, qualitative methods, and HIV/AIDS and human rights. We plan to continue to offer training in these areas and to expand training for Years 21-25 in clinical trials design and conduct, research laboratory and research pharmacy, biostatistics and data analysis, science writing and grants writing, clinical investigation, and research grants administration and management. We are proposing 14 long-term trainees; 2 Re-Entry grant awards; 304 short-term trainees (22 short course, 121 online course, 35 mentored/postdoctoral and 126 on site mentored trainees); 49 conference support trainees; and some 565 in-country workshop group trainees.